Start smaller than a speck of dust in a houseplant pot. Eat anything smaller than you, grow, and turn everything that hunted you into a snack: crumbs, cats, cars, cities and, eventually, the whole planet.
Build a Human Blood Extraction Factory! It's an incremental TD + Roguelike where your main goal is to torture little corpsys for Blood. Expand your towers and keep building upwards to reach different areas and fight boss and enemy waves, until your tree reaches heaven.